feat(pedagogy): gradient-levels audit + capability additions (§11.6)

[bradleypmartin]

Sub-issue of #233.

Per-scene pedagogical coverage audit for gradient-levels against APPM 2350 §11.6, and the resulting capability additions. Sub-epic — audit-phase findings get broken out into real sub-sub-issues at plan-doc time. Starter audit content TBD — to be filled in during the per-scene plan-doc phase.

Pedagogical anchor

§11.6 / VISION.md framing: gradient is perpendicular to level surfaces. The scene's headline pedagogical claim drives the audit: is this geometric fact made visible and felt, not just declared?

Audit (defer to plan doc)

• Walk the scene with the pedagogical-anchor question in hand; produce the starter list of gaps.
• Compare current capability against §11.6 syllabus content; flag missing or thin coverage.
• Identify candidate capability additions; triage into v1.0-scope vs. v1.x-deferred.

Composition

Paired with the gradient-levels narrative (#230). Plan together.